//
//  CaptchaView.m
//  验证码
//
//  Created by MS on 15-8-22.
//  Copyright (c) 2015年 YJ. All rights reserved.
//

#import "YJCaptchaView.h"
#define kRandomColor [UIColor colorWithRed:arc4random() % 256 / 256.0 green:arc4random() % 256 / 256.0 blue:arc4random() % 256 / 256.0 alpha:1.0]; 
#define kLineCount 6
#define kLineWidth 1.0
#define kCharCount 6
#define kFontSize [UIFont systemFontOfSize:arc4random() % 5 + 15]

@implementation YJCaptchaView
@synthesize changeStr,changeArr;

- (instancetype)initWithFrame:(CGRect)frame
{
    if (self = [super initWithFrame:frame]) {
        self.layer.cornerRadius = 5.0; //设置 layer 圆角半径
        self.layer.masksToBounds = YES; //隐藏边界
        self.backgroundColor = kRandomColor;
        //显示一个随机验证码
        [self changeCaptcha];
    }
    return self;
}

#pragma mark - 更换验证码,得到更换的验证码的字符串
-(void)changeCaptcha
{
    //<一>从字符数组中随机抽取相应数量的字符,组成验证码字符串
    //数组中存放的是全部可选的字符,可以是字母,也可以是中文
//    大小写+数字 版
//    self.changeArr= [[NSArray alloc]initWithObjects:@"0",@"1",@"2",@"3",@"4",@"5",@"6",@"7",@"8",@"9",@"A",@"B",@"C",@" D",@"E",@"F",@"G",@"H",@"I",@"J",@"K",@"L",@"M",@"N",@"O",@"P",@"Q",@"R",@"S",@"T", @"U",@"V",@"W",@"X",@"Y",@"Z",@"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",@"i",@"j",@"k ",@"l",@"m",@"n",@"o",@"p",@"q",@"r",@"s",@"t",@"u",@"v",@"w",@"x",@"y",@"z",nil];
//    数字 版
//    self.changeArr= [[NSArray alloc]initWithObjects:@"0",@"1",@"2",@"3",@"4",@"5",@"6",@"7",@"8",@"9",nil];
//    文明用语版
    self.changeArr = [[NSArray alloc]initWithObjects:@"你",@"吗",@"逼",@"大",@"爷",@"隔",@"壁",@"老",@"王",@"没",@"屁",@"眼",@"共",@"产",@"党",@"好", nil];
//    小写+数字 版
//    self.changeArr= [[NSArray alloc]initWithObjects:@"0",@"1",@"2",@"3",@"4",@"5",@"6",@"7",@"8",@"9",@"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",@"i",@"j",@"k ",@"l",@"m",@"n",@"o",@"p",@"q",@"r",@"s",@"t",@"u",@"v",@"w",@"x",@"y",@"z",nil];
    //如果能确定最大需要的容量,使用 initWithCapacity:来设置,好处是当元素个数不超过容量时,添加元素不需要重新分配内存
    NSMutableString * getStr = [[NSMutableString alloc]initWithCapacity:kCharCount];
    self.changeStr = [[NSMutableString alloc] initWithCapacity:kCharCount];
    //随机从数组中选取需要个数的字符,然后拼接为一个字符串
    for(int i = 0; i < kCharCount; i++)
    {
        NSInteger index = arc4random() % ([self.changeArr count] - 1);
        getStr = [self.changeArr objectAtIndex:index];
        self.changeStr = (NSMutableString *)[self.changeStr stringByAppendingString:getStr];
    }
}
#pragma mark - 点击View时调用
//因为当前类自身就是 UIView,点击更换验证码可以直接写到 这个方法中,不用再额外添加手势
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
    //    点击界面切换验证码
    [self changeCaptcha];
    //    setNeedsDisplay调用drawRect方法实现view的绘制
    [self setNeedsDisplay];
//    实时输出结果文字
    NSLog(@"%@",changeStr);
}

#pragma mark - 绘制界面
// UIView初始化自动调用
// 调用setNeedsDisplay自动调用

-(void)drawRect:(CGRect)rect{
    
    [super drawRect:rect];
    //设置随机背景颜色
    self.backgroundColor = kRandomColor;
    //获得要显示验证码字符串,根据长度,计算每个字符显示的大概位置
    NSString * text = [NSString stringWithFormat:@"%@",self.changeStr];
    CGSize cSize = [@"S" sizeWithAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:20]}];
    int width = rect.size.width / text.length - cSize.width;
    int height = rect.size.height - cSize.height;
    CGPoint point;
   
    //依次绘制每一个字符,可以设置显示的每个字符的字体大小、颜色、样式等
    float pX,pY;
    for (int i = 0; i < text.length; i++) {
        pX = arc4random()%width + rect.size.width / text.length * i;
        pY = arc4random() % height;
        point = CGPointMake(pX, pY);
        unichar c = [text characterAtIndex:i];
        NSString * textC = [NSString stringWithFormat:@"%C",c];
        [textC drawAtPoint:point withAttributes:@{NSFontAttributeName:kFontSize}];
    }
    
//调用 drawRect:之前,系统会向栈中压入一个 CGContextRef,调用 UIGraphicsGetCurrentContext()会取栈顶的 CGContextRef
    CGContextRef context = UIGraphicsGetCurrentContext();
//    设置画线宽度
    CGContextSetLineWidth(context, kLineWidth);
//    绘制干扰的彩色直线
    for (int i = 0; i < kLineCount; i ++ ) {
        
//        设置线的随机颜色
        UIColor * color = kRandomColor;
        CGContextSetStrokeColorWithColor(context, [color CGColor]);
        
//        设置线的起点
        pX = arc4random()% (int)rect.size.width;
        pY = arc4random()% (int)rect.size.height;
        CGContextMoveToPoint(context, pX, pY);
        
//        设置线的终点
        pX = arc4random()% (int)rect.size.width;
        pY = arc4random()% (int)rect.size.height;
        CGContextAddLineToPoint(context, pX, pY);
//        画线
        CGContextStrokePath(context);
    }
    
}

@end
